Cosopt (dorzolamide 2% / timolol 0.5%) is a twice-daily fixed-combination glaucoma eye drop that lowers intraocular pressure. On a private prescription in the UK in 2026, preservative-free Cosopt PF costs from around £15 per month, branded Cosopt from about £12, and generic dorzolamide-timolol from roughly £8. A consultant-led glaucoma assessment to confirm the diagnosis and start treatment starts from £250. Drops are usually the first-line treatment for glaucoma, used before laser or surgery is considered.
What is Cosopt?
Cosopt is a combined eye drop that brings together two well-established pressure-lowering medicines in one bottle. Dorzolamide is a carbonic anhydrase inhibitor that reduces the amount of fluid (aqueous humour) the eye produces. Timolol is a beta-blocker that does the same through a different mechanism. Used together, they lower eye pressure more than either alone — which is why a single combination drop can replace two separate bottles and simplify your daily routine.
It is prescribed for open-angle glaucoma and ocular hypertension, usually when a single drop has not lowered pressure enough, or to reduce the number of bottles a patient has to manage. Lowering eye pressure is the only proven way to slow glaucoma and protect the optic nerve and your field of vision over the long term.
When Cosopt is used
- Open-angle glaucoma where pressure needs lowering beyond a single agent
- Ocular hypertension with a high risk of progression to glaucoma
- Simplifying treatment — replacing two separate bottles with one
- Preservative sensitivity — the PF (preservative-free) version suits dry or reactive eyes
- Add-on therapy alongside a prostaglandin drop when more pressure control is needed
Not sure which glaucoma drop is right for you? A consultant glaucoma assessment includes pressure measurement, optic-nerve imaging and a visual-field check before any drop is started.
Book a glaucoma assessmentCosopt & dorzolamide-timolol options
Dorzolamide-timolol is available in three forms in the UK. Your consultant will recommend the most suitable based on your eye-surface health and how many drops you use a day. Preservative-free is preferred if you have dry eye or are on several drops long term.
If a beta-blocker such as timolol is not suitable — for example with asthma or certain heart conditions — your consultant may recommend an alternative combination such as Simbrinza (brinzolamide-brimonidine), Ganfort (bimatoprost-timolol) or Roclanda (netarsudil-latanoprost).
How to use Cosopt drops
Cosopt is used twice a day — one drop in the affected eye(s) in the morning and evening, about 12 hours apart. Correct technique helps the drop work and reduces side effects.
- Wash your hands and tilt your head back, or lie down.
- Gently pull down the lower eyelid to make a small pocket.
- Squeeze one drop into the pocket without touching the eye or eyelashes.
- Close the eye and press lightly on the inner corner (near the nose) for one to two minutes — this reduces how much medicine reaches the rest of the body.
- If you use more than one type of drop, leave at least 5 minutes between them.
If you wear contact lenses with preserved Cosopt, remove them first and wait 15 minutes before reinserting. Cosopt PF single-use vials avoid this issue.
What to expect & monitoring
Cosopt does not change your vision day-to-day — its job is to quietly protect the optic nerve by keeping pressure down. Most people tolerate it well, but a few side effects are worth knowing about.
First few minutes
A brief stinging or bitter taste at the back of the throat is common and settles quickly. Pressing the inner corner of the eye reduces the taste.
First two weeks
Eyes may feel slightly gritty or look a little red as they adjust. The preservative-free version reduces surface irritation.
4–6 weeks
A follow-up pressure check confirms the drop is working. Your consultant adjusts treatment if the target pressure has not been reached.
Ongoing
Glaucoma monitoring every 4–12 months with pressure checks, optic-nerve imaging and visual-field tests to confirm the disease stays stable.
Tell your consultant before starting Cosopt if you have asthma, COPD, a slow heart rate or heart problems, as the timolol component is a beta-blocker. If drops alone do not control pressure, the next steps are usually SLT laser or glaucoma surgery.
Cosopt cost in the UK
On a UK private prescription in 2026, the medicine itself is inexpensive — the value of private care is the consultant assessment, accurate diagnosis and ongoing monitoring that keep your sight safe.
- Generic dorzolamide-timolol (preserved): from £8 per month
- Branded Cosopt (preserved): from £12 per month
- Cosopt PF (preservative-free): from £15 per month
- Consultant glaucoma assessment: from £250, including pressure check, optic-nerve imaging and visual fields
- Insurance: recognised by Bupa, AXA, Aviva and others for the consultation and monitoring
For the full picture of glaucoma treatment costs — from drops to laser and surgery — see our glaucoma price guide or learn more about glaucoma treatment options.